Possible conflict between two computers on same router

[Jabba the hutt]

Hello everyone,
I'm experiencing an issue regarding my router connection. I have a router and 2 (sometimes they become 5, or even 6: another desktop pc, a netbook, 2 mobile phones) computers connected via WiFi. One is a MBP mid 2010, the other one is an Acer Notebook.
My problem is that when they are bot on the speed decreases, but especially on the acer one, whilst the mbp does well. they are both set for automatic dhcp.
I tried to make some speed tests online:


Only PC connected

Ping 34 ms
Download 13.5 Mbps
Upload 0.76 Mbps

Only MBP connected

Ping 31
Download 13.3 Mbps
Upload 0.75 Mbps

Both MBP and PC connected

PC_Ping 30
PC_Download 13.6 Mbps
PC_Upload 0.76 Mbps

MBP_Ping 30
MBP_Download 14.1 Mbps
MBP_Upload 0.75 Mbps

I couldn't figure out the issue of being slow, they seemed to work quite good together (i made one test at a time)

Then I tried to open 8 YouTube videos on the MBP, and I tried another test on each machine:

Both MBP and PC connected, 8 YouTube videos on the MBP

PC_Ping 64
PC_Download 5.3 Mbps
PC_Upload 0.55 Mbps

MBP_Ping 33
MBP_Download 9.04 Mbps
MBP_Upload 0.69 Mbps

It seemed like the PC suffered much more, even if it was not the one playing videos.

Then I tried to contemporarily run two tests. Because of human delay, I couldn't make them start togheter. When the MBP was in Upload phase, the PC was "Download"ing: its speed started falling down, until he reached 3 Mbps; then the MBP finished the test and the PC rose again to around 12 Mbps (in Download).

I don't know if it's an IP conflict issue, but both machines are set with automatically get IPs, and they both work together; the problem is that when the MBP is working it gets much more bandwidth, which is not normal. The PC slows a lot, and it's very annoying. The same thing happens when someone uses the Desktop PC: if the MBP is on, it surfs the net really slow.

Can anyone help me figure out what my problem is? Do I need to add more information?

[smirk]

I don't think I understand your problem. What makes you think that a problem exists, other than the normal consumption of bandwidth that each device must share?

[Quad5Ny]

Your ISP limits your bandwidth, its completely normal.

For example, if you have 15Mbps and one computer is using 8Mbps that only leaves 7Mbps for other devices.

Your not guaranteed 15Mbps per connection, its 15Mbps total.

[Weaselboy]

I'm not completely clear on your testing methodology. If you are saying just the presence of the second machine on the wifi slows down the first machine (even without the second machine downloading), what you may be seeing is a drop back to wireless G speeds when both machines connect.

What brand and model router do you have?

If it does not support simultaneous dual band , this can cause a slow down with multiple machines if they all do not support wireless N.